A Great Letter-to-the-Editor, 1: a Fundamental Contribution to Particle Physics

JF Ptak Science Books Post 2433

James Chadwick's introduction of the existence of the neutron made a "sly" entry into the general/popular scientific world--if such things could have personalities, then it would certainly be "humble". Except of course "humble" has no place in this vocabulary, except for instance like this, interpreting the poetry of the moment. Chadwiock's "Possible Existence of a Neutron" appeared inNature, 27 February 1932. volume 129, the revolutionary contribution appearing as a Letter to the Editor, in 1.25 columns, on page 312 of this issue of the journal. And in the "tradition" of the Alpher-Bethe-Gamow paper (the great paper on the Big Bang, appearing on April 1st 1948 in the Physical Review), it is another of very many instances of a major announcement being made as a "simple" letter to the editor. (Well, in the case of scientific letters, this is really just a shorter, quicker-to-publication avenue to publication, and not much at all like a letter-to-the-editor of the NYT. Still, the description has a nice ring to it.) This was the description of the neutron made after only about two weeks of experimentation.

"In 1932, Chadwick made a fundamental discovery in the domain of nuclear science: he proved the existence ofneutrons - elementary particles devoid of any electrical charge. In contrast with the helium nuclei (alpha rays) which are charged, and therefore repelled by the considerable electrical forces present in the nuclei of heavy atoms, this new tool in atomic disintegration need not overcome any electric barrier and is capable of penetrating and splitting the nuclei of even the heaviest elements. Chadwick in this way prepared the way towards the fission of uranium 235 and towards the creation of the atomic bomb."--NobelPrize.org

His next paper1--and perhaps the more famous of the two--appeared a few months later in May and contained the proof of the existence of the neutron, and was an epochal achievement int he understanding of the nucleus.

For this epoch-making discovery he was awarded the Hughes Medal of the Royal Society in 1932, and then the Nobel Prize for Physics in 1935. I think he may be the only recipient of the award who was also at one time a POW. (1914-1918 in Chadwick's case, going from there to a Ph.D. at Cambridge in 1921 and then to Rutherford's assistant shortly thereafter.)

Notes:

Chadwick, J. (1932). "The Existence of a Neutron". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences136 (830): 692. Another paper appeared int he next year,(1933). "Bakerian Lecture. The Neutron". Proceedings of the Royal Society A: Mathematical, Physical and Engineering